1. Technical Field
Embodiments of the present invention generally relate to a lubrication device and an image forming apparatus, such as, a copier, a printer, a facsimile machine, a plotter, or a multifunction peripheral (MFP) including at least two of copying, printing, facsimile transmission, plotting, and scanning capabilities, that includes the lubrication device.
2. Description of the Related Art
In electrophotographic image forming apparatuses, typically, after toner images are transferred from an image bearer onto an intermediate transfer member or sheets of recording media, a certain amount of toner is not transferred but remains on a surface of the image bearer. Such toner is hereinafter referred to as “untransferred toner”. To inhibit adverse effects of untransferred toner on subsequent image formation, image forming apparatuses usually include a cleaning device to remove the untransferred toner from the surface of the image bearer. Cleaning devices widely used include a cleaner, such as a cleaning blade or a cleaning brush, which slidingly contacts the surface of the image bearer to remove the untransferred toner from the image bearer. In such a cleaning device, when the cleaner is used for a long time and wears significantly, the cleaner chips or deforms. Then, the possibility of inconveniences, such as degradation of cleaning capability, increases. If the surface of the image bearer ears significantly, the operational life thereof is shortened.
To reduce frictional resistance between the surface of the image bearer and a component to contact the image bearer, typically the surface of the image bearer is lubricated. Since the lubrication of the image bearer reduces the frictional resistance between the cleaner and the surface of the image bearer, wear of the cleaner and the image bearer and inconveniences caused thereby are suppressed. Additionally, compared with pulverized toner, it is more difficult for a cleaning blade to remove spherical polymerization toner, which is widely used currently. The lubricant on the image bearer reduces adhesive force of the polymerization toner adhering to the surface of the image bearer. Accordingly, the surface of the image bearer is lubricated to facilitate removal of polymerization toner from the surface of the image bearer by the cleaning blade.
Additionally, in a portion where the cleaner contacts the image bearer, it is possible that plasticizer, charge controlling agent, and the like externally added to toner firmly adhere to the image bearer in a shape of film, which is a phenomenon called filming. The occurrence of filming can be inhibited by lubricating the image bearer. Additionally, it is known that, typically, the surface of the image bearer is easily degraded when a charging bias including an alternating voltage (current) component is applied thereto. The lubricant on the surface of the image bearer can suppress such degradation of the surface of the image bearer.
Although lubrication of the surface of the image bearer thus attains various effects, the effect is not sufficient if the amount of lubricant applied thereto is excessive or insufficient. If the amount of lubricant applied is insufficient, the amount of lubricant adhering to the surface of the image bearer tends to be insufficient locally. Portions where the amount of lubricant is insufficient can cause wear of the cleaner and the image bearer, hinder cleaning, or degrade the surface of the image bearer.
By contrast, if the amount of lubricant applied is excessive, it is possible that lubricant excessively adheres to a component such as a charging roller that contacts or approaches the image bearer, thus degrading capability of that component. Additionally, under humid conditions, excessive lubricant on the image bearer absorbs moisture and exhibits conductivity. Then, there arises a risk that electrostatic latent images are disturbed, resulting in image failure such as image deletion and image blurring.